The thought that a galaxy has been hiding in our sky for billions of years and that we only became aware of it because someone chose to examine historical data in a different way is subtly unsettling. That is essentially what happened with NGC 5084, a galaxy that astronomers had studied, cataloged, and mostly ignored. It was not thought to be particularly enigmatic. Then, almost by coincidence, it turned into one of the universe’s most bizarre objects.
In order to extract weak X-ray signals from archival data from the Chandra Observatory, scientists at NASA’s Ames Research Center in Silicon Valley, California, created a novel image analysis method. This method was not specifically developed to study NGC 5084.
| Category | Details |
|---|---|
| Subject | NGC 5084 — Galaxy with anomalous black hole orientation |
| Discovery Published | December 18, in The Astrophysical Journal |
| Lead Researcher | Alejandro Serrano Borlaff, Research Scientist, Bay Area Environmental Research Institute / NASA Ames |
| Location of Research | NASA’s Ames Research Center, Silicon Valley, California |
| Key Instrument Used | Chandra X-ray Observatory (archival data, some nearly 30 years old) |
| Supporting Observatories | Hubble Space Telescope, ALMA (Chile), Expanded Very Large Array, New Mexico |
| Analysis Method | SAUNAS — Selective Amplification of Ultra Noisy Astronomical Signal |
| Black Hole Orientation | Rotates at 90-degree angle to the galaxy’s own rotation plane |
| Key Finding | Four plasma plumes in an X-shape — an unprecedented structure |
| Significance | First known galaxy with a confirmed “tipped-over” supermassive black hole |
They were shocked by what they discovered when they applied this technique to that specific galaxy. The galaxy’s center was emitting four long plumes of plasma, or hot, charged gas.
Not two, not one. Four. There are two that stretch above and below the galactic plane, and two more that are flat inside it and cross the first pair to create a clear X-shape. There had never been a single galaxy with such a structure. It’s the kind of thing that forces you to review your work twice or three times before speaking aloud.
The study’s principal investigator, Alejandro Serrano Borlaff, compared the process of assembling the evidence to analyzing a crime scene in various lighting conditions. In this case, the analogy really works well because the team’s findings were layered rather than merely odd. The researchers dug into archives from Hubble and the Atacama Large Millimeter/submillimeter Array in Chile after the X-ray data caused controversy.
Hubble revealed a tiny, dusty inner disk circling the galaxy’s center. Not out of the ordinary on its own. However, compared to the rest of the galaxy, this disk is rotating at a perfect 90-degree angle. In actuality, the black hole at the center of the galaxy is tilted over on its side, lying horizontally while the surrounding galaxy rotates upright. It’s possible that the term “sideways” has never had such astronomical significance.
It’s difficult to ignore how outdated some of this data is. This discovery was made using portions of the Chandra archive that are almost thirty years old. The data was always there, waiting somewhere on servers. The faint low-brightness X-ray emissions were finally visible enough to be interpreted thanks to the SAUNAS method, which was published separately in the journal in May 2024.
That has a certain irony to it. The solution to one of the more shocking galactic riddles was already in the filing cabinet, and we have been constructing ever-more-powerful telescopes and sending them into deep space.
Naturally, this raises the question of how a supermassive black hole becomes overturned like a sleeping giant. To be honest, no one can say for sure just yet. A collision with another galaxy at some point in the distant past or the creation of a superheated gas chimney punching out through the top and bottom of the galactic plane are two theories put forth by astronomers studying NGC 5084. Violence is implied in both situations.
Violence on a cosmic scale, the kind that transforms entire structures over hundreds of millions of years, but still violence. According to Ames astrophysicist Pamela Marcum, the cross-shaped plumes provide a unique perspective on the galaxy’s past. There is a feeling that NGC 5084 has experienced a significant event that has left marks that are still discernible today in a variety of light wavelengths.
Beyond the immediate headlines, this discovery feels important because of what it suggests about everything we might be overlooking. It wasn’t obscure, NGC 5084. It wasn’t tucked away in some uncharted area of the sky. It was accessible, archived, and known data. Until there was a way to see it, the strangeness was invisible.
That poses a genuine and somewhat depressing question: How many other galaxies that have already been identified and set aside are concealing similar surprises?
The so-called “little red dots” that might be a completely new class of cosmic body are among the unexpected objects that the James Webb Space Telescope has been consistently revealing. The universe appears to have more structural diversity than our models could reasonably account for.
For the time being, additional observations of NGC 5084 are scheduled. The goal of research is to identify the event or series of events that led to the configuration they are observing. It is truly unclear if it was a merger, internal instability, or something else entirely.
The science is not failing because of that uncertainty. If anything, witnessing this kind of discovery serve as a reminder that the most fascinating scientific discoveries often begin with someone looking at something they are familiar with and then suddenly seeing it in a new way.
